Air-cooled exhaust muffler with frusto-conical body



Feb, 26, 1952 w. w. CUSHMIAN 2,586,788

AIR-COOLED EXHAUST MUFFLER WITH FRUSTO-CONICAL BODY Filed Jan. 26, 1948INVENTOR.

477073/VEY Patented Feb. 26, 1952 UNITED STATES PATENT OFFICE AIR-COOLEDEXHAUST MUFFLER WITH FRUSTO-CONICAL BODY (Granted under the act of March3, 1883, as amended April 30, 1928; 3'70 0. G. 757) 4 Claims.

The invention described herein, if patented, may be manufactured andused by or for the Government for governmental purposes Without thepayment to me of any royalty thereon.

The present invention relates to mufflers for the exhaust of internalcombustion engines and has for its primary object to provide a mufflerso designed as to eliminate the possibility of sparks or flames beingemitted therefrom.

Another object of the invention resides in the provision of a spark andflame arresting muffler which is of relatively simple and inexpensiveconstruction and yet which is highly effective in deadening the soundsemanating from the engine cylinders and in disposing of any sparks andflames prior to their reaching the rear end of the muffler.

Other objects and advantages of the invention will be apparent from thefollowing description when taken in connection with the accompanyingdrawings, in which Figure 1 is a side elevational view of the muffler,with parts broken away,

Figure 2 is a transverse sectional view taken on the line 2-2 of Figure1, and

Figure 3 is a similar view taken on line 3-3 of Figure 1.

Basically, the invention comprises a hollow elongated body flaredoutwardly and rearwardly to permit an expansion of the exhaust gases asthey leave the exhaust pipe and travel along the length of the muffler,in combination with means for rapidly diluting the exhaust gases withair to not only break down the sound waves but also to cool the gases toa temperature at which combustion will not take place and to a mixtureratio Well outside the range of combustibility, i. e., somewhat abovetwenty (20) parts of air to one (1) part of gasoline.

In the present illustration of the invention the numeral I indicates thebody of the muffler which is formed of any preferred metal and is offrusto-conical shape; the smaller end being secured to the rear end ofan exhaust pipe 2.

The mounting for the muffler comprises a ring 3 secured to the smallerend of the muffler by a plurality of webs 4 so that the ring isconcentrically arranged with respect to the mufller and is spacedinwardly of its walls. The muffler may be secured directly to theexhaust pipe 2, but

it is preferred that a short tubular member '5 be connected to the innerwall of the ring 3, by welding or otherwise, and that the tubular memberbe clamped to the exhaust pipe by means of a clamping ring 6 and bolt 1.The tubular member 5 is of course provided with one or more slits -8 topermit it to be contracted by the clamping ring 6 so as to firmly gripthe exterior of the exhaust pipe. The inner end of the tube that is, theend extending into the interior of the muffler is tapered as indicatedby the numeral 8 for the purpose of speeding the flow of exhaust gasesso as to increase the suction effect within the muffler as more fullyset forth hereinafter.

The smaller end of the muffler body I is flared outwardly as indicatedby the numeral 9 for the purpose of trapping a larger quantity ofatmospheric air and directing it into the muffler, and the body of themuffler itself is provided with a plurality of annular series ofstruck-up cupshaped tongues l0 associated with apertures H. The tonguesH] are directed toward the smaller end of the mufller body and thussupplement the action of the flared portion 9 of the muffler indirecting air into the interior of the muiller. It will be understood ofcourse that while these tongues and apertures If] and H are shown asuniformly arranged in annular series they may be arranged in anypreferred manner so long as they cover a major portion of the wall ofthe muiller and extend throughout its length.

In the operation of the muffler the current of exhaust gases passingthrough the tube 5 and narrowed end 8 provide a suction or aspiratingeffect so as to draw air in through the flared end 9 of the mufiler bodyto supplement the action of the forward movement of the vehicle and themuffler which is attached thereto. This high volume of air entering themuffler tends to dilute the gases and break up the sound waves and thisaction is supplemented by the many currents of air entering the mufflerthroughout its length by reason of the inclined tongues l0 and theapertures H associated therewith. Moreover, the flared construction ofthe muffler contributes to this same result by allowing the furtherexpansion of the gases as they travel rearwardly. By reason of theseseveral cooperating actions upon the exhaust gases the sound caused bythe explosions in the cylinders are materially reduced and thepossibility of sparks or flames passing outwardly from the rear end ofthe muffler is eliminated due to the fact that the large amount of airentering the muffler will dilute and cool the gases beyond the point atwhich combustion will be supported.

While the muffler has been described in some detail the invention is notso limited in scope, and it is therefore intended that the presentdisclosure be considered as illustrative of the invention rather than ina limiting sense.

I claim:

1. A muffler comprising an interiorly unobstructed, hollow, open-endedfrusto-conical body provided with an outwardly-flared portion on itssma11er end, means for securing the smaller end of the body to the endof the exhaust pipe of an engine in axial alignment therewith and withthe wall of the smaller end spaced radically outward of the wall of theexhaust pipe, the wall of said body provided with a plurality ofapertures, and means for directing air inwardly through said apertures.

2. A muffler comprising an interiorly unobstructed, hollow, open-endedfrusto-conical body having its exterior wall exposed to the atmosphereand provided with an outwardly-flared portion on its smaller end, meansfor securing the smalled end of the body to the end of the exhaust 20pipe of an engine in axial alignment therewith and with the wall of thesmaller end spaced radically outward of the wall of the exhaust pipe,and a plurality of tongues struck-up from said body and extending towardthe smaller end thereof.

3. A muffler comprising an interiorly unobstructed, hollow, open-endedfrusto-conical body having its exterior wall exposed to the atmosphereand provided with an outwardly-flared portion on its smaller end, thewall of said body provided with a plurality of apertures, means fordirecting air through said apertures, and an openended tube ofrelatively small diameter secured in the smaller end of thefrusto-conical body and having its inner end tapered.

4. A muffler comprising an open-ended, hollow, frusto-conical bodyhaving its exterior wall exposed to the atmosphere and provided with anoutwardly-flared portion at its smaller end, means for securing thesmaller end of the body to the exhaust pipe of an engine in axialalignment with the exhaust pipe, the wall of the body being radiallyspaced from the exhaust pipe, said mufller body being provided with aplurality of apertures, and means for directing air through saidapertures comprising cup-shaped tongues struckup from the body andextendin toward the smaller end thereof.

WALTON W. CUSHMAN.

REFERENCES CITED The 'following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 25 1,382,690 Stokes June 28, 19211,561,859 Kemble Nov. 17, 1925 2,389,059 Kurth Nov. 13, 1945 FOREIGNPATENTS 30 Number Country Date 608,447 France July 27, 1926 746,759France June 6, 1933 771,314 France Oct. 5, 1934

